A dinner: One woman and nine men. There is a traitor among them. 10 years after the Liberation of France, Marie Hélène Dumoulin, also known as Marie-Octobre gathers her former comrades of Resistance for one reception . She seeks to unmasked who has betrayed her friend Castille (the chief of a Resistance network) during the war. During the evening each person is suspected but there is just one guilty. A fascinating film with Nathalie Baye.